Cream the peanut butter and sugar in a bowl. (As much as I love my KitchenAid, I have found that this is a hand-stirring job). Beat in the baking powder. Add the egg. Mix until it is all well combined.

The dough will be sticky, so be prepared to get your hands messy. Roll some dough into a ball. (How big? That depends on you. I have found, however, that the smaller these cookies are, the better they hold together. Eat two instead of one!) Roll the ball into white sugar. Line a baking sheet, covered in parchment paper, with sugary balls of dough.

Bake in the oven for about ten minutes. You will know the cookies are done when they feel coherent, but still a little soft. Take the tray out of the oven and let the cookies rest for at least five minutes. Afterwards, carefully transfer them to a cooling rack. After ten minutes or so, they will have hardened and be glistening with sugar.